1. Field of the Invention
The invention relates to a method for the manufacture of substituted phosphanes and to a group of substituted phosphanes manufactured according to the method. Phosphanes are organic compounds of the trivalent phosphorus of the general formula P(R)R′)(R″), wherein R, R′ and R″, respectively, can be the same or different organic substituents. Phosphanes, phosphane oxides, sulfides or selenides are used as ligands in coordination compounds. They play a central role in controlling the activity and selectivity of catalysts.
Due to the commercial interest in these compounds, numerous groups of compounds have already been synthesized. Aromatically and heteroaromatically substituted phosphanes are also already known. They are used in various fields of engineering, e.g. as ligands in homogenous catalytic methods.
2. Description of the Related Art
Since ca. 1970, one has tried to realize increasingly complex substitution patterns in the substituents R, R′ and R″ to adapt the chemical and physical properties of these compounds to up-to-date problems in technical science. One can mention e.g. chelating phosphanes (several phosphorus centers in one molecule) and chiral phosphanes (for enantioselective catalyses), but also phosphanes carrying heterocycles at the substituents. One example of a heterocyclically substituted phosphane is tri(2-pyridyl)phosphane which is employed as a ligand in various, also technically relevant catalyses.
The easiest way to obtain phosphanes is by reacting compounds of the type PX3(X═Cl, Br, I, OR, NR2) with carbon nucleophiles (as a rule organometallic compounds, e.g. LiR, XMgR, MgR2, etc.). This restricts the variation possibilities for the groups R as no organometallic compounds can be obtained from many possible types and e.g. acidic groups are not tolerated. Therefore, a plurality of possible compounds is not yet known at all. Among them are heteroaromatically substituted phosphanes with pyrazole or pyrimidine groups at aromatic compounds that can not be manufactured in the way described above. Correspondingly substituted phosphane oxides, sulfides or selenides are also unknown up to now.
Thus, the object underlying the invention stated in the main claims is to provide a synthesis route for further phosphanes and to provide these phosphanes for controlling the activity and selectivity of catalysts.
This object is achieved by the invention by synthesizing heterocyclic substituents on aromatic groups by the introduction of acetyl groups. In this manner, previously unknown representatives of the compound families phosphanes, phosphane oxides, sulfides and selenides are made accessible. This was surprising as with aromatic phosphanes this synthesis route has neither been known nor expected before.